System for dyeing textiles and the like

ABSTRACT

An organic dyeing liquor, circulating hot through a vat filled with textiles to be dyed, is passed in a terminal stage through a cooler in cascade with a filter. As the temperature of the solvent progressively decreases, dyestuff is precipitated in the filter which is positioned close to the cooler, preferably in a common housing. Upon final rinsing with the substantially dyestuff-free solvent, impregnants or other treatment agents may be admixed therewith.

[ Sept. 18, 1973 SYSTEM FOR DYEING TEXTILES AND THE LIKE [75] Inventors:Heinrich Fiihring, Augsburg;

Johannes Helrnut Sieber, Aystetten, both of Germany [73] Assignee: Bowe,Bohler & Weber KG,

Augsburg, Germany 22 Filed: Sept. 27, 1971 21 Appl. No.: 183,915

[30] Foreign Application Priority Data 2,733,587 2/l956 McKendree 68/18F 3,206,951 9/1965 Sieber 68/18 R 3,674,650 7/1972 Fine 68/[8 F PrimaryExaminer-William I. Price Att0rneyl(arl F. Ross [57] ABSTRACT An organicdyeing liquor, circulating hot through a vat filled with textiles to bedyed, is passed in a terminal Sept. 25, 1970 Germany P 20 47 192.5

stage through a cooler in cascade with a filter. As the 52 US. Cl. 68/180, 68/18 F temperature of the solvent progressively decreases. 51 int.Cl. D06f 39/10 dyestuff is Precipitated in the filter which ispositioned 58 Field of Search 68/18 R, 18 F, 18 c, close to the cooler,preferably i a common h ingg 3 R Upon final rinsing with thesubstantially dyestuff-free solvent, impregnants or other treatmentagents may be References Cited admixed therewith.

UNITED STATES PATENTS 2,221,780 11/1940 Conrad et al. 68/13 R X 7Claims, 2 Drawing Figures CONDENSER 2 3 Z 2 Z 7 1 4 7 5 WATER SE A RA 7"02 DYE/N6 DE UN SOL VEN r RESERVOIR (HEATED) Patn'ted Sept. 18, 19733,759,011

CONDENSER Z3 Z2 Z7 g 7 5 J L igl l figig0z DY/NG//7 h a fir 26 DRUM 72 9\fl I 2 Biz ,0 comm F'LTE .I I A! l 24 8 9 m 6 18 V SOLVENT f 20EESE/EVO/l? 16 7.3

(HEATED) 5 SOLVENT 0U? 27 FILTER LAYER 35 4050255? z r F1 2 Z 29CO0LAIVT Ml Heinrich FUHRING Johannes H.SIEBER INVENTOR S Y s B marl jamAttorney SYSTEM FOR DYEING TEXTILES AND THE LIKE Our present inventionrelates to a system for dyeing a load of textile materials or the likewith the aid of a treatment liquor consisting essentially of an organicsolvent, e.g., perchloroethylene or a similar halogensubstitutedhydrocarbon, having a dyestuff dissolved therein.

Upon completion of the dyeing step proper, i.e., after the load has beensubstantially saturated with dye extracted from the solvent, a certainamount of the hot solution generally remains in the dyeing vessel whichmay be a vat or a rotating drum. A simple draining of this residualvolume is often inadmissible since the goods, particularly if they arein motion, would tend to develop objectionable creases and wrinkles. If,on the other hand, the liquor is allowed to cool in the vessel beforebeing discharged therefrom, some of the dyestuff remaining in solutionmay precipitate onto the goods and impair their colorfasteness; thus,upon the subsequent evaporation of the remaining traces of solvent, thecolor is likely to rub off onto adjoining objects. It has therefore beenhitherto necessary to rinse the goods rather vigorously, usually severaltimes, with pure solvent. In order to prevent the aforedescribedprecipitation of residual dyestuff on the goods, the rinsing fluid hadto be preheated to a temperature level close to that of the dyeingsolution, with progressively lower temperatures used during thesuccessive rinsing steps.

The general object of our invention is to provide an improved processand apparatus for dyeing textiles or similar goods in organic solutionswith avoidance of the aforestated drawbacks.

More particularly, our invention aims at reducing the energy input andincreasing the rate of solvent recovery in a system of this type.

These objects are realized, pursuant to the present invention, byrecirculating the spent dyeing liquor in a closed path through thetreatment vessel by way of a cooler and a filter, the latter removingthe residual dyestuff precipitated from the solution as the temperaturedrops. The circulated solvent, depleted of dyestuff, displaces theoriginal concentrate in the vessel and also entrains any particles ofcolorant that may have begun to settle on the goods.

If this recirculation process is carried to completion, i.e., to a pointwhere the solvent is at a temperature low enough to let it give offpractically all its solute, the substantially pure solvent may be usedfor the final rinse. The purified solvent, which no longer passesthrough the filter, may also be used as a vehicle for some otherfinishing agent with which the goods are to be treated.

Suitable dyestuffs, soluble in nonpolar' organic solvents such asperchloroethylene, trichloroethylene and carbon tetrachloride, includenitro, azo and anthraquinone compounds.

In order to avoid contamination of the conduits by precipitatingdyestuffs, the connection between the cooling stage and the filter stageshould be as short as possible. in a particularly advantageousembodiment, we dispose both stages in a common housing so that the fluidleaving the cooler is immediately intercepted by the filtering mass.This mass may be admixed in comminuted form with the fluid stream aheadof the filter elements which are preferably in the form of perforatedtubes whose surface becomes coated with the mass. Included in this massmay be an adsorbent, such as activated charcoal or fullers earth, havinga high affinity for the precipitate.

The invention will be described in greater detail hereinafter withreference to the accompanying drawing in which:

FIG. 1 is a block diagram of a system embodying our present improvement;and

FIG. 2 is an elevational view, partly in section, of a combined coolingand filtering stage included in the system of FIG. 1.

The system in FIG. 1 comprises a treatment vessel 1, such as a drumrotatable about a vertical axis, which is provided at the top with aloading aperture 3 and is supplied with treatment fluid through anincoming conduit 5 entering near its top, the fluid exiting at thebottom of the vessel via an outgoing conduit 4. it will be understoodthat these conduits may terminate at a stationary shell in which theperforated drum proper is journaled.

Conduits 4 and 5, which are provided with respective shutoff valves 8and 7,'form part of a closed path which includes a pump 6, a needle trap12 and further valves 9 and 26. Pump 6 is shown provided with a separateentrance port 6' by which an adjuvant, such as the aforementionedfinishing agents, may be admixed with the fluid stream.

A branch of this path, bypassing the valve 26, includes a cooler 13 anda filter 2 in cascade, this branch being controlled by a pair of valves10 and 11. Other branch lines lead from the high-pressure side of thepump 6, via a valve 18, to a solvent reservoir 19 and from thatreservoir, via a valve 25, to the low-pressure side of the pump.Reservoir 19 forms part of a separate circuit 23 which includes valves16 and 24, a still 17, a condenser 21 and a water separator 22. Filter 2has a drain emptying through a valve 20 into still 17.

Cooler 13 is a heat exchanger through which a cooling fluid iscirculated via pipes 14 under the control of a valve 15.

In operation, concentrated dyeing solution heated in reservoir 19 isdelivered to vessel 1 via open valves 25, 26 and 7 by pump 6, the othervalves being closed at this time. When the vessel has been filled andthe load is soaked, the solution can be recirculated by way of conduits4 and 5, valves 7, 8, 9 and 26 being open at this stage. Further heatingmeans, not shown, may be included in this path to maintain'the liquor atthe desired elevated temperature.

Upon termination of the dyeing process proper, valve 26 is closedwhereas valves 10 and 11 are opened to let the solution circulatethrough cooling stage 13 and filter stage 2.The progressive decrease ofthe fluid temperature causes the precipitation of residual dyestuff inthe filter 2 which may contain a mechanically acting microporous layer,e.g., of silica, admixed with an adsorbent such as activated charcoal.Next, the more or less depleted solution is deviated from the cooler 13and filter 2 to the still 17 by closing the valves 10 and 26 whileopening the valve 16, the vapors being reliquefied in condenser 21 andreturned to the reservoir 19 via valve'24 and water separator 22. If thecirculating solvent has been sufficiently purified, it may- FIG. 2 showsa preferred construction of the filter stage 2 which in this instanceincorporates the heat exchanger schematically indicated at 13 in FIG. 1.This device comprises a generally cylindrical housing 27 formed at thetop with a manifold 27 which opens into conduit 5. Conduit 4, carryingthe solution discharged from vessel 1, communicates with a T-shaped pipe29 inside the housing, this pipe passing through a centrally disposedheat exchanger 30 and opening into the housing at opposite ends 33 and34. A peripheral array of filter elements 28 (only two shown) surroundsthe tubular heat exchanger 30, each of these elements comprising aperforated tube 36 whoseperipheral surface is coated with a permeabledeposit 35 of filter particles as described above. The layer 35 may bedislodged, after termination of normal operation, by the admission ofhigh-pressure fluid into manifold 27' through conduit 5, the tubes 28communicating with this manifold at the top while opening into the mainhousing chamber at the bottom. Coolant is circulated through the heatexchanger 30 via a pair of pipes 31 and 32.

As will be apparent, the filter elements 28 are disposed downstream ofthe cooler 30 within housing 27, with reference to the direction ofsolvent flow indicated by arrows in FIG. 2; this corresponds to therelative positioning of the cooler and the filter 2 in FIG. 1.

The filter 2 could, of course, also be used to extract other entrainedmatter from the fluid stream.

Before switching to the still 17, the pure solvent may be recirculatedone or more times through the closed path used for the initial dyeingstep, by way of valve 26 and with valves 10 and 11 closed. It is at thisstage that an impregnant or other treatment agent may be introduced intothe flow at port 6' to impart a desired finish to the goods in vessel 1.

We claim:

1. A system for dyeing a load of textile materials or the like,comprising:

a dyeing vessel adapted to receive a load to be dyed;

a supply of hot dyeing liquor consisting essentially of an organicsolvent with a dyestuff dissolved therein;

conduit means for delivering said liquor to said vessel and forestablishing a closed path for the circulation of the liquor throughsaid vessel;

cooling means for said liquor in said path; downstream filter means forresidual dyestuff inserted in said path downsteram of said coolingmeans, said cooling means being operative to lower the temperature ofsaid liquor to a level facilitating the precipitation of said residualdyestuff in said filter means; and pump means in said path forsuccessively driving said liquor through said cooling means and saidfilter means before returning same to said vessel.

2. A system as defined in claim 1 wherein said cooling means immediatelyprecedes said filter means.

3. A system as defined in claim 2, further comprising a common housingfor said cooling means and said filter means, said housing having aninlet for said liquor connected to said cooling means and an outlet forsaid liquor connected to said filter means.

4. A system as defined in claim 3 wherein said cooling means comprises aheat exchanger disposed centrally in said housing, said filter meanscomprising an array of tubular filter elements surrounding said heatexchanger and opening into said housing, the latter being provided witha manifold connecting said elements to said outlet.

5. A system as defined in claim 1 wherein said supply includes a solventreservoir, a still and a condenser forming part of a closed circuitbypassing said cooling means and said filter means, the latter beingprovided with a drain connectable to said still.

6. A system as defined in claim 1 wherein said pump means is providedwith an entrance port for the admixture of a treatment agent with thecirculating solvent.

7. A system for dyeing a load of textile materials or the like,comprising:

a dyeing vessel adapted to receive a load to be dyed;

a supply of hot dyeing liquor consisting essentially of an organicsolvent with a dyestuff dissolved therein;

conduit means for delivering said liquor to said vessel and forestablishing a closed path for the circulation of the liquor throughsaid vessel;

cooling means for said liquor in said path;

filter means for residual dyestuff inserted in said path downstream ofsaid cooling means; and

pump means in said path for successively driving said liquor throughsaid cooling means and said filter means before returning same to saidvessel;

said supply including a solvent reservoir, a still and a condenserforming part of a closed circuit bypassing said cooling means and saidfilter means, the latter being provided with a drain connectable to saidstill.

I i t

2. A system as defined in claim 1 wherein said cooling means immediatelyprecedes said filter means.
 3. A system as defined in claim 2, furthercomprising a common housing for said cooling means and said filtermeans, said housing having an inlet for said liquor connected to saidcooling means and an outlet for said liquor connected to said filtermeans.
 4. A system as defined in claim 3 wherein said cooling meanscomprises a heat exchanger disposed centrally in said housing, saidfilter means comprising an array of tubular filter elements surroundingsaid heat exchanger and opening into said housing, the latter beingprovided with a manifold connecting said elements to said outlet.
 5. Asystem as defined in claim 1 wherein said supply includes a solventreservoir, a still and a condenser forming part of a closed circuitbypassing said cooling means and said filter means, the latter beingprovided with a drain connectable to said still.
 6. A system as definedin claim 1 wherein said pump means is provided with an entrance port forthe admixture of a treatment agent with the circulating solvent.
 7. Asystem for dyeing a load of textile materials or the like, comprising: adyeing vessel adapted to receive a load to be dyed; a supply of hotdyeing liquor consisting essentially of an organic solvent with adyestuff dissolved therein; conduit means for delivering said liquor tosaid vessel and for establishing a closed path for the circulatioN ofthe liquor through said vessel; cooling means for said liquor in saidpath; filter means for residual dyestuff inserted in said pathdownstream of said cooling means; and pump means in said path forsuccessively driving said liquor through said cooling means and saidfilter means before returning same to said vessel; said supply includinga solvent reservoir, a still and a condenser forming part of a closedcircuit bypassing said cooling means and said filter means, the latterbeing provided with a drain connectable to said still.